Refrigerant cycle device with ejector and refrigerant branch structure for the same

ABSTRACT

A branch structure is provided on an upstream side of an ejector in a refrigerant cycle device, for branching and supplying refrigerant to a nozzle of the ejector and to an evaporator connected to a refrigerant suction port of the ejector. For example, the branch structure is constructed with an introduction pipe part for introducing the refrigerant, and at least two arm parts branched out from the introduction pipe part. The two arm parts are substantially symmetrical with respect to the introduction pipe part, while being positioned substantially under the same condition with respect to a direction of gravity.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2005-236657 filed on Aug. 17, 2005, the contents of which are incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a refrigerant cycle device having an ejector, and to a refrigerant branch structure for branching a flow of refrigerant in the refrigerant cycle device.

2. Description of the Related Art

A refrigerant cycle device is known in JP Patent No. 3322263 (corresponding to U.S. Pat. No. 6,477,857 and U.S. Pat. No. 6,574,987), which includes an accumulator connected to a downstream side of an ejector. In this refrigerant cycle device, an outlet for a liquid-phase refrigerant of the accumulator is connected to an inlet of an evaporator, and an outlet of the evaporator is connected to a refrigerant suction port of the ejector.

In this prior art cycle, refrigerant is decompressed and expanded by a nozzle of the ejector with a small path area of the refrigerant, and the refrigerant flowing from the evaporator is drawn using a decrease in pressure caused by a high-speed flow of the refrigerant in decompression and expansion. Speed energy of the refrigerant in expansion is converted into pressure energy by a diffuser of the ejector, resulting in an increase in refrigerant pressure (suction pressure of a compressor). This can decrease a driving power of the compressor, thereby improving an operational efficiency of the cycle.

In this cycle, however, a flow rate of the refrigerant supplied to the evaporator depends only on a suction capability of the ejector. Thus, a small difference between high and low pressures of the refrigerant cycle causes a decrease in input of the ejector, a degradation in suction capability of the ejector, and a decrease in flow rate of the refrigerant of the evaporator. Accordingly, it is difficult for the evaporator to accurately perform its cooling capacity.

Thus, US 2005/0178150A1 and US 2005/0268644A1 propose a refrigerant cycle device provided with a branch path which causes the flow of the refrigerant to branch on an upstream side of a nozzle of an ejector into an ejector suction port. Furthermore, the branch path is provided with a throttle mechanism for adjusting the pressure and flow rate of the refrigerant, and an evaporator. Since the refrigerant flow branches on the upstream side of the ejector, and the branched refrigerant is drawn into a refrigerant suction port, the branch path is in a parallel connected relation to the ejector. This can supply the refrigerant to the evaporator through the branch path using not only the refrigerant suction capability of the ejector, but also the refrigerant suction and discharge capabilities of the compressor. Even when an input level of the ejector is reduced, and the suction capability of the ejector is decreased, the degree of decrease in flow rate of the refrigerant supplied to the evaporator in this refrigerant cycle can be made smaller.

In this refrigerant cycle device, the diffuser of the ejector converts the speed energy of the refrigerant into the pressure energy to increase the pressure of the refrigerant. When only a vapor-phase refrigerant with a smaller density than that of the liquid-phase refrigerant flows into the nozzle of the ejector, the speed energy of the refrigerant becomes small, which makes it difficult to increase the pressure of the refrigerant by the diffuser. As a result, the driving power of the compressor is not decreased readily, thereby reducing the operational efficiency of the refrigerant cycle.

The branched refrigerant on the upstream side of the nozzle of the ejector generally contains the liquid-phase refrigerant and the vapor-phase refrigerant. These phases differ from each other in specific gravity, and hence are apt to be influenced by gravity or kinetic momentum of the refrigerant, so that they are individually mixed in the refrigerant. Thus, the liquid-phase refrigerant is likely to branch while being deflected toward the evaporator side or the nozzle side of the ejector. The condition of deflection of the vapor-phase and liquid-phase refrigerants may be varied according to a change in the operational condition of the cycle. This may lead to variations in flow rate ratio of the branched refrigerant.

For this reason, the liquid-phase refrigerant is allowed to branch appropriately in a branch portion on the upstream side of the nozzle of the ejector so as not to be deflected toward the evaporator side or the nozzle side of the ejector, such that the liquid-phase refrigerant is supplied reliably to the nozzle side of the ejector. However, in US 2005/0178150A1 and US 2005/0268644A1, there are no disclosure how a branch portion should be set from the view point of supplying the liquid-phase refrigerant to the nozzle of the ejector with reliability.

SUMMARY OF THE INVENTION

In view of the foregoing problems, it is an object of the present invention to reliably supply liquid-phase refrigerant from a branch portion on an upstream side of a nozzle of an ejector to the nozzle of the ejector for a refrigerant cycle device.

It is another object of the present invention to allow an ejector to work stably by preventing an influence of a deflected condition of vapor-phase and liquid-phase refrigerants in a refrigerant cycle device.

It is a further another object of the present invention to reduce an influence of a deflected condition of vapor-phase and liquid-phase refrigerants in a refrigerant cycle device.

It is a further another object of the present invention to provide a refrigerant cycle device with an ejector, which can be stably operated while improving its cycle capacity.

According to an aspect of the present invention, a branch structure for branching and supplying refrigerant to a nozzle of an ejector and to an evaporator connected to a refrigerant suction port of the ejector includes an introduction pipe part for introducing the refrigerant, and at least two arm parts branched out from the introduction pipe part. Furthermore, the two arm parts are substantially symmetrical with respect to the introduction pipe part, while being positioned substantially under the same condition with respect to a direction of gravity. Therefore, when the branch structure is used for a refrigerant cycle device with the ejector, the ejector function can be stably obtained by reducing the variation in distribution difference between the vapor-phase and liquid-phase refrigerants. For example, the two arm parts are arranged substantially in a U shape having one end connected to the introduction pipe part.

According to another aspect of the present invention, a branch structure for branching and supplying refrigerant to a nozzle of an ejector and to an evaporator connected to a refrigerant suction port of the ejector includes an introduction pipe part for introducing the refrigerant, and at least first and second branch parts branched out from the introduction pipe part. Furthermore, the first branch part extends in an extension direction of the introduction pipe part, and the second branch part extends substantially perpendicularly to the extension direction of the introduction pipe part. Therefore, refrigerant can be stably introduced to the nozzle of the ejector. For example, the introduction pipe is positioned so as to extend in the direction of gravity, or/and the second branch part is positioned to extend in a horizontal direction from an extension of the introduction part.

According to a further another aspect of the present invention, a refrigerant cycle device includes a condenser for cooling and condensing refrigerant, a branch portion for branching a flow of refrigerant on a downstream side of the condenser into first and second streams, an ejector that includes a nozzle for decompressing and expanding refrigerant of the first stream flowing from the branch portion and a refrigerant suction port from which refrigerant is drawn by a high-speed refrigerant flow jetted from the nozzle, a throttle member for decompressing and expanding refrigerant of the second stream flowing from the branch portion, and an evaporator for evaporating refrigerant decompressed by the throttle member and having an outlet coupled to the refrigerant suction port. In the refrigerant cycle device, the branch portion branches the refrigerant flow such that a ratio of a liquid-phase refrigerant in refrigerant flowing to the nozzle is approximately equal to a ratio of a liquid-phase refrigerant in refrigerant flowing to the evaporator. Thus, it is possible for the ejector to stably work while preventing an influence of a deflected condition of vapor-phase and liquid-phase refrigerants in the refrigerant cycle device. For example, a flow direction of the refrigerant flowing from the branch portion toward the nozzle, and a flow direction of the refrigerant flowing from the branch portion toward the evaporator are arranged substantially on the same plane. Alternatively, the flow direction of the refrigerant flowing from the branch portion toward the nozzle, and the flow direction of the refrigerant flowing from the branch portion toward the evaporator are arranged substantially symmetrically with respect to a flow direction of the refrigerant flowing into the branch portion. Furthermore, the branch portion may be constructed with an introduction pipe part for introducing refrigerant, and at least two arm parts branched out from the introduction pipe part. In this case, the two arm parts may be substantially symmetrical with respect to the introduction pipe part, while being positioned substantially under the same condition with respect to a direction of gravity.

According to a further another aspect of the present invention, the branch portion branches the refrigerant flow such that a ratio of a liquid-phase refrigerant in refrigerant flowing to the nozzle is equal to or greater than a ratio of a liquid-phase refrigerant in the refrigerant flowing to the evaporator. In this case, the liquid refrigerant can be stably divided and supplied to the nozzle of the ejector. For example, a flow direction of refrigerant flowing into the branch portion may be arranged on a substantially same straight line as a flow direction of refrigerant flowing to the nozzle from the branch portion. Alternatively, the flow direction of refrigerant flowing to the nozzle from the branch portion may be oriented downward substantially in a vertical direction. Furthermore, the branch portion may be constructed with an introduction pipe part for introducing the refrigerant, and at least first and second branch parts branched out from the introduction pipe part. In this case, the first branch part may extend in an extension direction of the introduction pipe part, and the second branch part may extend substantially perpendicularly to the extension direction of the introduction pipe part.

According to a further another aspect of the present invention, a refrigerant cycle device includes a compressor for compressing and discharging refrigerant, a branch portion for branching a flow of refrigerant discharged from the compressor in a vapor-phase condition or a vapor-liquid two-phase condition near a saturated vapor line into first and second streams, a first condensing part for cooling and condensing refrigerant of the first stream branched by the branch portion, a second condensing part for cooling and condensing refrigerant of the second stream branched by the branch portion, an ejector that includes a nozzle for decompressing and expanding refrigerant flowing from the first condensing part and a refrigerant suction port from which refrigerant is drawn by high-speed refrigerant flow ejected from the nozzle, a throttle member for decompressing and expanding the refrigerant flowing from the second condensing part, and an evaporator for evaporating refrigerant decompressed by the throttle member and coupled to the refrigerant suction port. Because the refrigerant is branched by the branch portion before being decompressed in the first and second condensing parts, the refrigerant can be stably and accurately divided into both the nozzle of the ejector and the throttle member. For example, the branch portion may be provided between a discharge port of the compressor and an upstream side of the first and second condensing parts in a refrigerant flow. Alternatively, the first and second condensing parts may be constructed to form a condenser, and the branch portion may be provided on a refrigerant inlet side inside the condenser.

According to a further another aspect of the present invention, a refrigerant cycle device includes a condenser for cooling and condensing refrigerant, a vapor-liquid separator for separating the refrigerant on a downstream side of the condenser into a vapor-phase refrigerant and a liquid-phase refrigerant and for allowing the liquid-phase refrigerant to flow out therefrom, a branch portion for branching a flow of the liquid-phase refrigerant from the vapor-liquid separator into first and second streams, an ejector that includes a nozzle for decompressing and expanding liquid refrigerant flowing from the first stream and a refrigerant suction port from which refrigerant is drawn by high-speed refrigerant flow ejected from the nozzle, a throttle member for decompressing and expanding liquid refrigerant flowing from the second stream, and an evaporator for evaporating refrigerant decompressed by the throttle member and coupled to the refrigerant suction port. Accordingly, liquid refrigerant can be accurately supplied to both the nozzle of the ejector and the throttle member. For example, the branch portion may be provided in a receiver of the vapor-liquid separator. Alternatively, the branch portion may be located on a downstream side of a liquid-phase refrigerant outlet of the vapor-liquid separator, or the branch portion may be provided integrally with the ejector.

The term “substantially equal” or “approximately equal” described above means not only that the ratio of the liquid-phase refrigerant in the refrigerant flowing to the ejector side is completely identical to that of the liquid-phase refrigerant in the refrigerant flowing to the evaporator side, but also that these rates may be substantially equal to each other even with a small difference.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional objects and advantages of the present invention will be more readily apparent from the following detailed description of preferred embodiments when taken together with the accompanying drawings. In the drawings:

FIG. 1 is a cycle configuration diagram showing a refrigerant cycle device according to a first embodiment of the present invention;

FIG. 2 is a sectional view of a three-way joint of the refrigerant cycle device of the first embodiment;

FIG. 3 is a cycle configuration diagram showing a refrigerant cycle device according to a second embodiment of the present invention;

FIG. 4 is a sectional view of a three-way joint of the refrigerant cycle device of the second embodiment;

FIG. 5 is a cycle configuration diagram showing a refrigerant cycle device according to a third embodiment of the present invention;

FIG. 6 is a cycle configuration diagram showing a refrigerant cycle device according to a fourth embodiment of the present invention;

FIG. 7 is a cycle configuration diagram showing a refrigerant cycle device according to a fifth embodiment of the present invention;

FIG. 8 is a diagram for explaining a refrigerant state in a vapor-liquid two-phase condition near a saturated vapor line;

FIG. 9 is a cycle configuration diagram showing a refrigerant cycle device according to a sixth embodiment of the present invention;

FIG. 10 is a sectional view of an ejector in the refrigerant cycle device of the sixth embodiment; and

FIG. 11 is a cycle configuration diagram showing a refrigerant cycle device according to a seventh embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

FIG. 1 shows an example in which a refrigerant cycle device according to a first embodiment is used for a refrigeration system for a vehicle. The refrigeration system for a vehicle in the embodiment is adapted to cool the inside of a room to a very low temperature, for example, about −20 degrees centigrade.

In a refrigerant cycle device 10 shown in FIG. 1, a compressor 11 is adapted to suck, compress, and discharge a refrigerant. The compressor 11 is rotatably driven by an engine for a traveling vehicle (not shown) via an electromagnetic clutch 11 a and a belt. In the embodiment, the compressor used is a swash-plate type variable displacement compressor capable of variably controlling a discharge capacity sequentially based on a control signal from the outside.

More specifically, the pressure of a swash plate chamber (not shown) is controlled using a discharge pressure and a suction pressure of the compressor 11 to change an angle of inclination of the swash plate, thereby changing a piston stroke. This changes the discharge capacity sequentially in a range of about 0 to 100%. This change in discharge capacity can adjust a refrigerant discharge capability.

The discharge capacity is a geometric capacity of a working space for sucking and compressing the refrigerant, and corresponds to a cylinder capacity defined between a top dead center and a bottom dead center of the piston stroke.

The control of pressure of the swash plate chamber will be described below. The compressor 11 includes an electromagnetic capacity control valve 11 b, which incorporates therein a pressure reactive mechanism (not shown) for generating a force F1 by a low pressure of the refrigerant on the suction side of the compressor 11, and an electromagnetic mechanism (not shown) for generating an electromagnetic force F2 opposed to the force F1 generated by the refrigerant low pressure Ps.

The electromagnetic force F2 of the electromagnetic mechanism is determined by a control current In output from an air conditioning controller 23 as described later. The ratio of the high-pressure refrigerant to the low-pressure refrigerant which are introduced into the swash plate chamber is changed by a valve body (not shown) which is displaced according to the force F1 responding to the refrigerant low pressure Ps and the electromagnetic force F2, thereby changing the pressure of the swash plate chamber.

Furthermore, the compressor 11 can have its discharge capacity changed sequentially in the range of about 0 to 100% by adjustment of the pressure of the swash plate chamber. Decreasing the discharge capacity to about 0% allows the compressor 11 to be substantially in an operation-stopped state. Thus, the compressor 11 may have a clutchless construction in which a rotating shaft of the compressor 11 is constantly connected to a vehicle engine via a pulley or a belt V.

The condenser 12 is a heat exchanger connected to the discharge side of the compressor 11 for exchanging heat between the high-pressure refrigerant discharged from the compressor 11 and an external air (air outside the interior of the vehicle) blown by a blower 12 a for the condenser, and for condensing the high-pressure refrigerant by dissipating the heat from the refrigerant. The blower 12 a for the condenser is driven by an electromagnetic motor 12 b for driving, which is adapted to be rotatably driven when a voltage output from the air conditioning controller 23 is applied thereto.

An inner heat exchanger 13 is connected to a refrigerant downstream side of the condenser 12 via a refrigerant pipe 14 a, and exchanges heat between the high-pressure refrigerant flowing from the condenser 12 and the low-pressure refrigerant drawn into the compressor 11. The heat exchange between the refrigerants at the inner heat exchanger 13 allows the refrigerant having passed the refrigerant pipe 14 to be cooled, and thus a difference in enthalpy (cooling capacity) of the refrigerant between an inlet and an outlet of the evaporators 19, 22, which will be described later, can be increased.

The refrigerant pipe 14 is constructed with a refrigerant pipe 14 a for connecting the condenser 12 with the inner heat exchanger 13, and a refrigerant pipe 14 b for connecting the inner heat exchanger 13 with the three-way joint 15. The three-way joint 15 is a pipe joint which branches the refrigerant flowing from the refrigerant pipe 14 b into a refrigerant pipe 16 for guiding the refrigerant to the nozzle 18 a of the ejector 18 as will be described below, and a branch pipe 17 for guiding the refrigerant to the refrigerant suction port 18 b.

The details of the three-way joint 15 will be given below with reference to FIG. 2. The three-way joint 15 is made of the same material (for example, aluminum) as those of the refrigerant pipes 14 and 16 and the branch pipe 17. The three-way joint is composed of an introduction pipe part 15 a having a substantially linear shape, and a branch pipe part 15 b having a substantially U-like shape.

One end of the introduction pipe part 15 a is connected to the refrigerant pipe 14 b, and the other end is connected to a connection hole 15 c disposed at a substantial center of a U-shaped bottom of the branch pipe part 15 b. One end of the branch pipe part 15 b is connected to the refrigerant pipe 16, and the other end is connected to a branch pipe 17 a. These connections are performed with brazing so as to prevent a leak of the refrigerant.

That is, as shown in FIG. 2, the three-way joint 15 is constructed to have a branch portion A (branch area A) on the refrigerant flow downstream side of the connection hole 15 c. Furthermore, in the embodiment, a flow direction of the refrigerant flowing from the branch portion A to the refrigerant pipe 16 (the direction of arrow B in FIG. 2), and a flow direction of the refrigerant flowing from the branch portion A to the branch pipe 17 a (the direction of arrow C in FIG. 2) are set substantially symmetrically with respect to a flow direction of the refrigerant flowing into the three-way joint 15. Furthermore, both the direction of arrow B and the direction of arrow C are positioned on a substantially horizontal plane.

In the embodiment, the introduction pipe part 15 a is a straight pipe, and can have enough length to rectify the flow of the refrigerant to a straight flow. The branch pipe part 15 b provides at its center the branch portion A serving as a connection part at which the introduction pipe part 15 a is opened and connected. The branch pipe part 15 b provides two arm parts extending symmetrically with reference to a pipe axis of the introduction pipe part 15 a, that is, with respect to an axis of the extension of the pipe part 15 a.

These arm parts of the branch pipe part 15 b are positioned such that the flows of the refrigerants are symmetric with respect to the pipe axis of the introduction pipe part 15 a. Therefore, the curved shapes of the refrigerant flows in the two arm pipes of the branch pipe part 15 b in the horizontal and vertical directions are symmetrical to each other. For example, the two arm pipes can be located on the common plane such that respective parts of both arm pipes are positioned at the same height to each other as viewed from the branch portion A. For example, the two arm pipes can be positioned on the same horizontal plane.

As a result, as viewed from the branch portion A, the distribution of the vapor-phase refrigerant and the liquid-phase refrigerant in both the arm pipes, and distribution variations in both the arm pipes are symmetric. This can reduce the influences of the distribution and the variations, so that the refrigerant can be divided at a predetermined ratio in both the arm pipes. For example, the distribution of the vapor-phase and liquid-phase refrigerants occurs in the same manner at each arm part, and is changed in the same manner at each arm part even if the operational condition of the cycle is changed.

Then, the other end of the refrigerant pipe 16 is connected to the ejector 18. The ejector 18 serves as decompression means for decompressing the refrigerant, as well as refrigerant transport and circulating means for circulating the refrigerant by a suction effect (trapping effect) of the flow of the refrigerant ejected at high speed.

The ejector 18 includes the nozzle 18 a for decompressing and expanding the refrigerant isoentropically by throttling a path area of the refrigerant flowing via the refrigerant pipe 16 to a small level, and the refrigerant suction port 18 b provided in communication with a refrigerant jet port of the nozzle 18 a. The refrigerant suction port 18 b is provided for sucking the vapor-phase refrigerant from the second evaporator 22 as will be described later.

On the downstream side of the nozzle 18 a and the refrigerant suction port 18 b, a mixing portion 18 c is provided for mixing the high-speed refrigerant flow from the nozzle 18 a and the drawn refrigerant from the refrigerant suction port 18 b. A diffuser 18 d serving as a pressure-increasing portion is provided on the downstream side of the mixing portion 18 c.

The diffuser 18 d is formed in a shape that gradually enlarges the path area of the refrigerant, and has a function of decelerating the refrigerant flow to increase the refrigerant pressure, that is, a function of converting speed energy of the refrigerant into pressure energy.

A first evaporator 19 is connected to the downstream side of the refrigerant flow of the diffuser 18 d of the ejector 18. The first evaporator 19 is a heat sink which is adapted to exchange heat between the refrigerant and the air blown by a blower 19 a for the evaporator, and to exhibit a heat absorbing effect by evaporating the refrigerant. The blower 19 a for the evaporator is driven by an electric motor 19 b for driving, and the electric motor 19 b for driving is rotatably driven when the voltage output from the air conditioning controller 23 is applied.

To the downstream side of the refrigerant flow of the first evaporator 19, an accumulator 20 (gas-liquid separator) is connected. The accumulator 20 is a vapor-liquid separator for separating the refrigerant into liquid-phase and vapor-phase refrigerants. An outlet for the vapor-phase refrigerant of the accumulator 20 is connected to a suction side of the compressor 11 via the inner heat exchanger 13 described above.

The branch pipe 17 is a pipe for connecting the three-way joint 15 with the refrigerant suction port 18 b of the ejector 18. In the branch pipe 17, a fixed throttle 21 and the second evaporator 22 are disposed. The branch pipe 17 is constructed of the branch pipe 17 a for connecting the three-way joint 15 and the fixed throttle 21, a branch pipe 17 b for connecting the fixed throttle 21 and the inlet of the second evaporator 22, and a branch pipe 17 c for connecting the outlet of the second evaporator 22 and the refrigerant suction port 18 b.

The fixed throttle 21 performs flow-rate adjustment and decompression of the refrigerant which is to flow into the second evaporator 22, and is constructed of an orifice in the embodiment, for example. It is apparent that the fixed throttle may be constructed of a capillary tube.

The second evaporator 22 is a heat sink for evaporating the refrigerant and exhibiting a heat-absorbing effect. In the embodiment, the first evaporator 19 and the second evaporator 22 are connected integrally. More specifically, components of the first evaporator 19 and the second evaporator 22 are made of aluminum, and integrally connected to each other with brazing.

Thus, air blown by the above-mentioned blower 19 a for the evaporator flows in a direction of arrow D. First, air blown by the blower 19 a is cooled by the first evaporator 19, and then by the second evaporator 22 in the air flow direction. That is, the same space to be cooled is cooled by the first evaporator 19 and the second evaporator 22.

The air conditioning controller 23 (A/C ECU) is constructed of the known microcomputers, including a CPU, a ROM, and a RAM, and peripheral circuits. The air conditioning controller 23 performs various types of calculation and processing based on a control program stored in the ROM thereby to control operations of the above-mentioned various devices 11 a, 11 b, 12 b, and 19 b.

Furthermore, the air conditioning controller 23 receives detection signals from various sensors, and various kinds of operational signals input from an operational panel (not shown). As a group of sensors, for example, an outside air sensor or the like is provided for detecting a temperature of the outside air (a temperature of air outside of the vehicle). The operational panel is provided with a temperature setting switch for setting a cooling temperature of the space to be cooled, and an air conditioning operation switch or the like for outputting an operational command signal of the compressor 11.

Now, an operation of the refrigerant cycle device with the above-mentioned arrangement according to the embodiment will be described below. When an air conditioning operational switch is turned on, the electromagnetic clutch 11 a is energized and then engaged based on a control output from the air conditioning controller 23, so that a rotary driving force is transmitted from an engine for a traveling vehicle to the compressor 11.

When a control current In is output from the air conditioning controller 23 to the electromagnetic capacity control valve 11 b based on the control program, the compressor 11 sucks and compresses the vapor-phase refrigerant to discharge the compressed refrigerant therefrom.

The high-temperature and high-pressure vapor-phase refrigerant compressed by and discharged from the compressor 11 flows into the condenser 12. In the condenser 12, the high-temperature and high-pressure refrigerant is cooled and condensed by the external air. The high-pressure refrigerant after having passed from the condenser 12 and having heat radiated therefrom exchanges heat with a low-pressure vapor-phase refrigerant flowing from the accumulator 20 in the inner heat exchanger 13.

The refrigerant flow from the inner heat exchanger 13 flows into the three-way joint 15. The refrigerant flowing into the three-way joint 15 is divided into the refrigerant flow directed to the ejector 18 via the refrigerant pipe 16, and the refrigerant flow directed to the fixed throttle 21 via the branch pipe 17 a.

The three-way joint 15 is disposed such that the flow direction of the refrigerant flowing from the branch portion A to the refrigerant pipe 16 (the direction of arrow B in FIG. 2), and the flow direction of the refrigerant flowing from the branch portion A to the branch pipe 17 a (the direction of arrow C in FIG. 2) are oriented on a substantially horizontal plane. Thus, the liquid-phase refrigerant flowing into the three-way joint 15 is divided without being influenced by the gravity.

The direction of arrow B and the direction of arrow C are set substantially symmetrically with respect to the refrigerant flow direction flowing from the refrigerant pipe 14 b into the three-way joint 15. The refrigerant flowing into the three-way joint 15 is divided into the refrigerant pipe 16 side and the branch pipe 17 a side without being influenced by kinetic momentum in the flow direction of the refrigerant from the refrigerant pipe 14 b to the branch portion A.

In the embodiment, two arm parts of the three-way joint 15 are formed symmetrically with respect to the introduction pipe part 15 a, and are positioned at the same height or the like when viewed from the branch portion A. Thus, these arm parts are positioned under the same condition with respect to the direction of gravity as viewed from the branch portion A. This reduces the difference in distribution of the vapor-phase and liquid-phase refrigerants caused due to the gravity, between the insides of the respective arm parts, each extending from the branch portion A, and also reduces the fluctuations of the difference in distribution, so that the refrigerant can be divided into each arm part at a predetermined ratio.

Thus, the refrigerant is branched at the branch portion A such that a ratio of a liquid-phase refrigerant in the refrigerant flowing to the nozzle 18 a of the ejector 18 is substantially equal to that of a liquid-phase refrigerant in the refrigerant flowing to the second evaporator 22 side. As a result, the liquid-phase refrigerant can reliably be flowing into the nozzle 18 a of the ejector 18.

The refrigerant flowing into the ejector 18 is decompressed and expanded by the nozzle 18 a. In decompression and expansion, the pressure energy of the refrigerant is converted into the speed energy, whereby the refrigerant is ejected from the ejection port of the nozzle 18 a at high speed. The ejector 18 sucks the refrigerant after passing the second evaporator 22, from the refrigerant suction port 18 b.

The refrigerant ejected from the nozzle 18 a and the refrigerant drawn into the refrigerant suction port 18 b are mixed by the mixing portion 18 c on the downstream side of the nozzle 18 a to flow into the diffuser 18 d. In this diffuser 18 d, the expansion of the refrigerant path area converts the speed energy of the refrigerant into the pressure energy thereof, so as to an increase in pressure of the refrigerant.

In the present embodiment, the liquid-phase refrigerant reliably enters the nozzle 18 a of the ejector 18, so that the diffuser 18 d can exhibit a pressurization capability readily, thus preventing the deterioration of the operational efficiency of the cycle.

The refrigerant flowing from the diffuser 18 d of the ejector 18 flows into the first evaporator 19, where the low-pressure refrigerant absorbs heat from the blown air by the blower 19 a for the evaporator, and then evaporates. The refrigerant after passing through the first evaporator 19 flows into the accumulator 20 to be divided into the vapor-phase refrigerant and the liquid-phase refrigerant.

The vapor-phase refrigerant flowing from the accumulator 20 flows into the inner heat exchanger 13 to exchange heat with the high-pressure refrigerant having passed the refrigerant pipe 14. Then, the vapor-phase refrigerant flowing from the inner heat exchanger 13 is drawn into the compressor 11 to be compressed again.

On the other hand, the refrigerant flowing into the branch pipe 17 is compressed by the fixed throttle 21 to become the low-pressure refrigerant, which flows into the second evaporator 22. In the second evaporator 22, the low-pressure refrigerant flowing therethrough absorbs heat from the blown air cooled by the first evaporator 19, and then evaporates.

Then, the refrigerant which evaporates at the second evaporator 22 is drawn from the refrigerant suction port 18 b of the ejector 18, and then mixed with the liquid-phase refrigerant passing through the nozzle 18 a at the mixing portion 18 c to flow into the first evaporator 19.

As mentioned above, in the embodiment, since the refrigerant on the downstream side of the diffuser 18 d of the ejector 18 can be supplied to the first evaporator 19, and the refrigerant on the branch pipe 17 side can be supplied to the second evaporator 22 via the fixed throttle 21, the first evaporator 19 and the second evaporator 22 can provide the cooling capacity simultaneously.

At this time, the refrigerant evaporation pressure of the first evaporator 19 is a pressure of the refrigerant after pressurization by the diffuser 18 d. And the outlet of the second evaporator 22 is connected to the refrigerant suction port 18 b of the ejector 18. Therefore, the lowest pressure after the decompression by the nozzle 18 a can be applied to the second evaporator 22. Thus, the refrigerant evaporation pressure (refrigerant evaporation temperature) of the second evaporator 22 can be lower than that of the first evaporator 19.

Furthermore, since the liquid-phase refrigerant can be supplied reliably from the branch portion A to the nozzle 18 a of the ejector 18, the pressurization effect of the diffuser 18 d can be exhibited, and the suction pressure of the compressor 11 can be increased. As a result, an amount of the compression work by the compressor 11 can be decreased, thereby showing a power-saving effect.

Second Embodiment

In the second embodiment, as shown in FIG. 3, a three-way joint 30 which is constructed of connection pipes, each having a substantially linear shape, is employed. The second embodiment may be the same as the first embodiment in other components except for the above-mentioned joint.

The details of the three-way joint 30 will be described with reference to FIG. 4. The material of the three-way joint 30 is the same as those of the first embodiment, and the three-way joint 30 is constructed of an input-output pipe part 30 a having a substantially linear shape and a branch pipe part 30 b having a substantially linear shape. The input-output pipe part 30 a extends vertically and has upper and lower parts with respective to the branch portion E. The upper part of the input-output pipe part 30 a provides an introduction pipe part. The lower part of the branch pipe part 30 a and the branch pipe part 30 b provide arm parts branching from the introduction pipe part.

One end of the input-output pipe part 30 a is connected to the refrigerant pipe 14 b, and the other end thereof is connected to the refrigerant pipe 16. Furthermore, at a substantially center of the input-output pipe part 30 a, a connection hole 30 c connected to the branch pipe part 30 b is provided. One end of the branch pipe part 30 b is connected to the input-output pipe part 30 a at the connection hole 30 c, and the other end is connected to the branch pipe 17 a. These connections are performed with brazing so as to prevent a leak of the refrigerant.

Therefore, the branch portion E (branch area) is constructed in the vicinity of the connection hole 30 c. Furthermore, in a refrigerant cycle device of the embodiment, the three-way joint 30 is disposed such that a flow direction of the refrigerant flowing from the refrigerant pipe 14 b to the branch portion E (the direction of arrow F in FIG. 4), and a flow direction of the refrigerant flowing from the branch portion E to the refrigerant pipe 16 (the direction of arrow G in FIG. 4) are set downward in the vertical direction on the same straight line.

An operation of the embodiment with the above-mentioned arrangement will be described below. Likewise the first embodiment, the refrigerant discharged from the compressor 11 is cooled and condensed by the condenser 12. The cooled refrigerant passes through the inner heat exchanger 13, and then flows into the three-way joint 30 to be divided into a refrigerant flow directed to the ejector 18 via the refrigerant pipe 16, and a refrigerant flow directed to the fixed throttle 21 via the branch pipe 17.

The three-way joint 30 is disposed such that the flow direction of the refrigerant flowing from the refrigerant pipe 14 b to the branch portion E, and the flow direction of the refrigerant flowing from the branch portion E to the refrigerant pipe 16 are oriented downward in the vertical direction on the same straight line. Thus, the liquid-phase refrigerant flowing from the refrigerant pipe 14 into the three-way joint 30 is likely to flow from the branch portion E to the refrigerant pipe 16 due to the kinetic momentum and gravity rather than flowing from the branch portion E to the refrigerant pipe 17 a.

In this way, the ratio of the liquid-phase refrigerant in the refrigerant flowing from the branch portion E to the nozzle 18 a of the ejector 18 via the refrigerant pipe 16 can be substantially equal to or greater than that of the liquid-phase refrigerant in the refrigerant flowing to the second evaporator 22 via the branch pipe 17 a.

The ejector 18 has the suction effect and pressurization effect of the refrigerant flowing from the branch portion E to the nozzle 18 a of the ejector 18, as is the case with the first embodiment. In addition, the first evaporator 19 has the cooling effect of this refrigerant, which is then drawn into the compressor 11 again. The second evaporator 22 has the cooling capacity of the refrigerant flowing from the branch portion E to the second evaporator 22, as is the case with the first embodiment, while the refrigerant is being drawn into the refrigerant suction port 18 b of the ejector 18.

In this embodiment, the lower part of the input-output pipe part 30 a, which is one of the arm parts, is extended as an extension from the upper part of the input-output pipe part 30 a, which is an introduction pipe. In addition, the branch pipe part 30 b, which is the other of the arm parts, is extended substantially perpendicularly to the extension of the introduction pipe part. The introduction pipe is positioned to extend in the gravity direction. The branch pipe part 30 b, which is the other of the arm parts, is positioned horizontally from the extension of the introduction pipe.

As mentioned above, in the embodiment, the first evaporator 19 and the second evaporator 22 can perform the cooling operation simultaneously. Moreover, the refrigerant evaporation pressure (refrigerant evaporation temperature) of the second evaporator 22 can be made lower than that of the first evaporator 19.

Furthermore, the refrigerant flowing from the refrigerant pipe 14 b into the three-way joint 30 is likely to flow out toward the nozzle 18 a of the ejector 18. For example, even when a cooling heat load is small, or even when a refrigerant flow rate or velocity is slow in a refrigerator or the like for domestic use or for commercial use, the liquid-phase refrigerant can be supplied accurately to the nozzle 18 a by the kinetic momentum of the refrigerant and the gravity. As a result, this embodiment can obtain the effect described in the first embodiment.

Third Embodiment

Although in the first embodiment the three-way joint 15 for branching the refrigerant flow is disposed on the downstream side of the condenser 12, the invention is not limited thereto. In this embodiment, as shown in FIG. 5, the three-way joint 15 and the condenser 12 described in the first embodiment are not provided, a condenser 31 is provided instead, and a branch portion H for branching refrigerant at a position between a refrigerant discharge port of the compressor 11 and a refrigerant inlet of the condenser 31. This branch portion H is used to branch the refrigerant flow by using the same pipe joint as the three-way joint 15 of the first embodiment.

The condenser 31 is a heat exchanger for exchanging heat between the high-pressure refrigerant discharged from the compressor 11 and an external air (i.e., air outside the interior of the vehicle) blown by the blower 31 a for the condenser to cool and condense the high-pressure refrigerant. The blower 31 a for the condenser is driven by an electric motor 31 b for driving, which is adapted to be rotatably driven when the voltage output from the air conditioning controller 23 is applied.

Furthermore, the condenser 31 includes a first condensing part 31 c and a second condensing part 31 d. One of the refrigerant streams branched by the branch portion H is connected to the inlet of the first condensing part 31 c of the condenser 31, and the other refrigerant stream is connected to the inlet of the second condensing part 31 d.

The first condensing part 31 c radiates heat only from one of the refrigerants branched by the branch portion H to condense the one refrigerant, and the second condensing part 31 d radiates heat only from the other of the refrigerants branched by the branch portion H to condense the other one, whereby the refrigerant flowing into the first condensing part 31 c and the refrigerant flowing into the second condensing part 31 d are not mixed to each other.

In this embodiment, the first condensing part 31 c and the second condensing part 31 d are integrally combined vertically with a screw via a bracket. The blower 31 a for the condenser is disposed so as to cool both the refrigerants of the first condensing part 31 c and the second condensing part 31 d at the same time.

The refrigerant outlet of the first condensing part 31 c is connected to the refrigerant pipe 16, and the refrigerant outlet of the second condensing part 31 d is connected to the refrigerant pipe 17 a. In the embodiment, the first evaporator 19 is not provided, and only an evaporator 22 performs the cooling operation, thus constituting the cycle. For simplifying the system, the inner heat exchanger 31 is not provided in the cycle shown in FIG. 5. However, the third embodiment may be the same as the first embodiment in other components except for the above-mentioned joint.

An operation of the third embodiment with the above-mentioned arrangement will be described below. The refrigerant discharged from the compressor 11 is divided into the first condensing part 31 c and the second condensing part 31 d. At this time, the refrigerant at the branch portion H is a vapor-phase refrigerant discharged form the compressor 11, and does not contain a liquid-phase refrigerant.

Thus, at the branch portion H, the vapor-phase refrigerant can be appropriately divided into the first condensing part 31 c and the second condensing part 31 d without being influenced by the kinetic momentum and gravity. The high-temperature and high-pressure vapor-phase refrigerant is cooled and condensed by the external air at the first condensing part 31 c, and also the high-temperature and high-pressure vapor-phase refrigerant is cooled and condensed by the external air at the second condensing part 31 d.

The liquid-phase refrigerant flowing from the first condensing part 31 c flows into the nozzle 18 a of the ejector 18 via the refrigerant pipe 16, and the ejector 18 has the suction effect and the pressurization effect of the refrigerant, causing the refrigerant to flow into the accumulator 20, and to be drawn into the compressor 11 again.

On the other hand, the liquid-phase refrigerant flowing from the second condensing part 31 d becomes the low-pressure refrigerant by the fixed throttle 21 via the branch pipe 17 a to flow into the evaporator 22. In the evaporator 22, the low-pressure refrigerant flowing therethrough absorbs heat from the blown air blown by the blower 19 a for the evaporation, and then evaporates. The refrigerant flowing from the evaporator 22 is drawn into the refrigerant suction port 18 b of the ejector 18, and mixed with the liquid-phase refrigerant having passed the nozzle 18 a by the mixing portion 18 c to flow into the accumulator 20.

As mentioned above, in the embodiment, the branch portion H is disposed between the refrigerant discharge port of the compressor 11 and the refrigerant inlet of the condenser 31, so that the vapor-phase refrigerant which does not contain the liquid-phase refrigerant can branch appropriately at the branch portion H.

Furthermore, after the refrigerant branched, heat is radiated in the condenser 31 such that the refrigerant is condensed respectively in the first and second condensing parts 31 c, 31 d. This can supply the liquid-phase refrigerant to the nozzle 18 a of the ejector 18 with reliability. As a result, the refrigerant pressure is increased at the diffuser 18 d of the ejector 18, thereby decreasing the driving power of the compressor, thus enables improvement of the operational efficiency of the cycle.

Fourth Embodiment

Although in the third embodiment the branch portion H for branching the refrigerant flow is disposed between the refrigerant discharge port of the compressor 11 and the refrigerant inlet of the condenser 31, the invention is not limited thereto. In this embodiment, as shown in FIG. 6, the branch portion H and the condenser 31 are not provided, and a condenser 32 is provided.

The condenser 32 is a heat exchanger for exchanging heat between the high-pressure refrigerant discharged from the compressor 11 and the external air blown by the blower 12 a for the condenser to condense the high-pressure refrigerant by dissipating the heat from the refrigerant. The blower 32 a for the condenser is driven by an electric motor 32 b for driving, which is adapted to be rotatably driven when the voltage output from the air conditioning controller 23 is applied.

Furthermore, in the condenser 32, a branch portion I is provided for branching the flow of the high-pressure refrigerant discharged from the compressor 11 while the heat is radiated. The condenser 32 includes a first condensing part 32 c for radiating heat from one of the refrigerants branched by the branch portion I to condense the one refrigerant, and a second condensing part 32 d for radiating heat from the other of the refrigerants branched to condense the other one.

The branch portion I is located on the refrigerant inlet side within the condenser 32. At the branch portion 1, the heat is not radiated sufficiently from the refrigerant at the branch portion 1, and thus the refrigerant is in a vapor-phase condition or in a vapor-liquid two-phase condition near a saturated vapor line, as shown in FIG. 8. That is, within the condenser 32, a small-capacity heat exchanger 32 e may be located at the upstream position of the branch portion 1.

The first condensing part 32 c radiates heat only from one of the refrigerants branched by the branch portion I to condense the one refrigerant, and the second condensing part 32 d radiates heat only from the other of the refrigerants branched by the branch portion I to condense the other one, such that the refrigerant flowing into the first condensing part 32 c and the refrigerant flowing into the second condensing part 32 d are not mixed to each other.

The first condensing part 32 c and the second condensing part 32 d are integrally connected vertically in the same way as that of the third embodiment. The blower 32 a for the condenser is disposed such that the refrigerants in both the first condensing part 32 c and the second condensing part 32 d can be cooled simultaneously. Furthermore, the refrigerant outlet of the first condensing part 32 c is connected to the refrigerant pipe 16, and the refrigerant outlet of the second condensing part 32 d is connected to the branch pipe 17 a.

The refrigerant cycle with this arrangement of the embodiment is operated to cause the refrigerant discharged from the compressor 11 to flow into the condenser 32, and to branch into the first condensing part 32 c and the second condensing part 32 d by the branch portion I within the condenser 32.

The refrigerant at the branch portion I is positioned on the refrigerant inlet side within the condenser 32, and thus is in the vapor-phase condition or the vapor-liquid two-phase condition near the saturated vapor line without being cooled sufficiently. Thus, the refrigerant at the branch portion I is a vapor-phase refrigerant which does not contain any liquid-phase refrigerant, or which contains only a small amount of liquid-phase refrigerant.

Accordingly, the branch portion I can branch the vapor-phase refrigerant into the first condensing part 32 c and the second condensing part 32 d. At the first condensing part 32 c, the high-temperature and high-pressure vapor-phase refrigerant is cooled and condensed by the external air, and the liquid-phase refrigerant flowing from the first condensing part 32 c flows into the nozzle 18 a of the ejector 18 via the refrigerant pipe 16. Thus, the liquid-phase refrigerant can be supplied reliably to the nozzle 18 a of the ejector 18. This embodiment can obtain the same effect as that of the third embodiment.

Fifth Embodiment

In the fifth embodiment, as shown in FIG. 7, the condenser 12 similar to that of the first embodiment is provided, and a vapor-liquid separator 33 for dividing the refrigerant into vapor-phase and liquid-phase refrigerants is provided on the downstream side of the condenser 12.

Furthermore, the refrigerant pipe 16 and the branch pipe 17 a are connected to a liquid-phase refrigerant outlet of the vapor-liquid separator 33. Thus, in the embodiment, a branch portion J is provided in a liquid-phase refrigerant reservoir within the vapor-liquid separator 33. The fifth embodiment may be the same as the third embodiment in other components except for the above-mentioned components.

The refrigerant cycle device with the above-mentioned arrangement of the embodiment is operated to cause the refrigerant discharged from the compressor 11 to be cooled by the condenser 12, and to be separated into vapor-phase and liquid-phase refrigerants by the vapor-liquid separator 33. The liquid-phase refrigerant stored in the vapor-liquid separator 33 is branched to the ejector 18 side and the evaporator 22 side. As a result, the liquid-phase refrigerant can be supplied reliably to the nozzle 18 a of the ejector 18. This embodiment can obtain the advantages similar to that of the third embodiment.

Furthermore, although in the embodiment, the branch portion J is located in the liquid-phase refrigerant receiver, the invention is not limited thereto. Alternatively, a branch portion may be provided in the pipe on the downstream side of a liquid-phase refrigerant outlet of the vapor-liquid separator 33, and the refrigerant pipe 16 and the refrigerant pipe 17 a may be connected to each other. Also in this case, the same effect as the third embodiment may be obtained.

For example, a condenser including a condensing part, a vapor-liquid separating cell, and a supercooling part which are arranged along the refrigerant flow in sequence may be used as the condenser 12. In addition, a branch portion may be provided on the downstream side of the supercooling part. With this arrangement, an end of the refrigerant pipe 16 can be opened at an area for the liquid-phase refrigerant of the refrigerant path, so that the liquid-phase refrigerant can be supplied reliably to the ejector 18.

As a result, even when the size and shape of each component of the ejector 18 is set on the assumption that the liquid-phase refrigerant is supplied to the nozzle 18 a, the function of the ejector 18 can be provided reliably. From another viewpoint, the ends of the refrigerant pipe 16 and the branch pipe 17 can be opened to the liquid-phase refrigerant area of the refrigerant path, thereby decreasing uneven distribution of the vapor-phase and liquid-phase refrigerants, and an influence of the variations in the uneven distribution. This can branch the refrigerant at a predetermined ratio.

Sixth Embodiment

Although in the first embodiment the refrigerant flow is branched by the three-way joint 15, the invention is not limited thereto. In this embodiment, as shown in FIG. 9, the three-way joint 15, the refrigerant pipe 16, and the ejector 18 are not provided, and an ejector 40 including a branch portion therein is provided.

First, the ejector 40 will be described below with reference to FIG. 10. The ejector 40 is a variable flow rate type ejector, and is constructed of a housing 40 a, a nozzle 40 b, a diffuser 40 c, and a path area adjustment mechanism 41. The housing 40 a serves to fix and hold components of the ejector 40. The housing 40 a is provided with a refrigerant flow inlet 40 d through which the refrigerant from the refrigerant pipe 14 b flows to flow into the ejector 40, a branch refrigerant flow outlet 40 e through which the refrigerant flowing from the inlet 40 d flows to a branch path 17 a, and a refrigerant suction port 40 f which is provided in communication with a refrigerant jet hole 40 h of the nozzle, as will be described below, and which is adapted to suck the refrigerant from the branch path 17 c.

Here, the refrigerant flow inlet 40 d is connected with the refrigerant pipe 14 b, the branch refrigerant flow outlet 40 e is connected to the branch path 17 a, and the refrigerant suction port 40 f is connected to the branch path 17 c. These parts are connected with brazing so as to prevent a leak of the refrigerant from connection parts.

The nozzle 40 b is adapted to decompress and expand the refrigerant isoentropically by throttling the path area of the refrigerant to a small level, and is fixed inside the housing.

As shown in FIG. 10, the nozzle 40 b is provided with a refrigerant inflow hole 40 g which connects the refrigerant flow inlet 40 d and the inside of the nozzle 40 b, and through which the refrigerant flows into the nozzle 40 b, the refrigerant jet hole 40 h through which the refrigerant flowing from the refrigerant inflow hole 40 g into the nozzle 40 b is jetted to a mixing portion 40 j as will be described below, and a branch refrigerant outflow hole 40 i which communicates the inside of the nozzle 40 b and the branch refrigerant flow outlet 40 e.

Thus, the refrigerant flowing from the refrigerant inflow hole 40 g into the nozzle 40 b flows from the refrigerant jet hole 40 h and the branch refrigerant outflow hole 40 i into the outside of the nozzle 40 b. In the embodiment, a branch portion K (branch area K) is constructed in the vicinity of the branch refrigerant outflow hole 40 i within the nozzle 40 b as shown in FIG. 10.

On the refrigerant flow downstream side of the refrigerant jet hole 40 h within the housing 40 a, the mixing portion 40 j is provided. The mixing portion 40 j mixes the refrigerant jetted from the refrigerant jet hole 40 h and the refrigerant drawn from the refrigerant suction port 40 f.

The diffuser 40 c serving as the pressure-increasing portion is disposed on the refrigerant flow downstream side of the mixing portion 40 j. The diffuser 40 c is formed in a shape that gradually enlarges the path area of the refrigerant, and performs a function of decelerating the refrigerant flow to increase the refrigerant pressure, that is, a function of converting the speed energy of the refrigerant into the pressure energy.

Furthermore, the diffuser 40 c includes a diffuser flow outlet 40 l through which the refrigerant having passed the diffuser 40 c flows out. It should be noted that the diffuser 40 c is connected with brazing or the like so as to prevent a leak of the refrigerant. The diffuser may be integrally formed with the housing 40 a by cutting work or the like.

The path area adjustment mechanism 41 is fixed over the upper part side of the nozzle 40 b of the housing 40 a (in the upward direction denoted by the arrow of FIG. 10) with a screw or the like via a seal or the like so as to prevent the leak of the refrigerant. The ejector 40 and the path area adjustment mechanism 41 are integrally formed.

The path area adjustment mechanism 41 includes a needle 41 a and a driving portion 41 b. The needle 41 a includes a slender sharp-pointed tip having a substantially similar shape to that of an inside path of the nozzle 40 b, and an axis part connected with a rotor 41 c. The axis part of the needle 41 a is connected with the rotor 41 c with a screw-like connector. Thus, the rotation of the screw-like connector allows the axis part of the needle 41 a to move in a longitudinal direction within the nozzle 40 b (in a vertical direction (top-bottom direction) denoted by the arrow in FIG. 10).

The driving portion 41 b is constructed of a known stepping motor. When a control signal (pulse signal) is output from the air conditioning controller 23, the rotor 41 c of the driving portion 41 b is adapted to rotate. When the rotor 41 rotates, the screw-like connector on the rotor 41 c side rotates, causing the needle 41 a to move. Therefore, when the needle 41 a is approaching to the refrigerant jet hole 40 h (in a downward direction denoted by the arrow in FIG. 10), the flow rate of the refrigerant jetted from the refrigerant jet hole 40 h is decreased. Conversely, when the needle 41 a is moved away from the refrigerant jet hole 40 h (in an upward direction denoted by the arrow in FIG. 10), the flow rate of the refrigerant ejected from the refrigerant jet hole 40 h is increased.

In contrast, the branch refrigerant outflow hole 40 i is disposed in such a position that even when the needle 41 a is moved, the flow rate of the refrigerant passing through the branch refrigerant outflow hole 40 i is not changed. Furthermore, the ejector 40 is disposed such that in the refrigerant cycle device 10 of the embodiment, the path area adjustment mechanism 41 is oriented upward in the vertical direction, and the diffuser 40 c is oriented downward in the vertical direction.

Thus, the flow direction of the refrigerant from the refrigerant pipe 14 b to the branch portion K (the direction of arrow L in FIG. 10), and the flow direction of the refrigerant from the branch portion K to the branch pipe 17 a (the direction of arrow M in FIG. 10) are oriented horizontally to each other. The flow direction of the refrigerant from the branch portion K to the refrigerant jet hole 40 h (the direction of arrow N in FIG. 10) is oriented downward in the vertical direction (top-bottom direction).

In the sixth embodiment, the refrigerant flow direction toward the nozzle 40 b means a direction of the refrigerant flowing from the branch portion K to the refrigerant jet hole 40 h. The sixth embodiment may be the same as the first embodiment in other components except for the above-mentioned components.

An operation of the sixth embodiment with the above-mentioned arrangement will be described below. The refrigerant discharged from the compressor 11 is cooled and condensed by the condenser 12, likewise the first embodiment. The refrigerant condensed passes through the inner heat exchanger 13 to flow into the ejector 40, and is divided into the refrigerant flow oriented from the branch portion K to the branch pipe 17 a, and into the refrigerant flow oriented toward the refrigerant jet hole 40 h.

The air conditioning controller 23 outputs the control signal to the path area adjustment mechanism 41 such that a degree of supercooling of the refrigerant on the outlet side of the condenser 12 is in a predetermined range, and then adjusts the flow rate of the refrigerant ejected from the refrigerant jet hole 40 h.

Furthermore, since the ejector 40 is disposed as mentioned above, the liquid-phase refrigerant flowing from the refrigerant pipe 14 to the three-way joint 30 is likely to flow out to the refrigerant jet hole 40 h due to the gravity, rather than flowing out to the refrigerant pipe 17 a from the branch portion E.

In this way, the ratio of the liquid-phase refrigerant in the refrigerant flowing to the refrigerant jet hole 40 h can be equal to or greater than that of the liquid-phase refrigerant in the refrigerant flowing to the second evaporator 22 via the branch pipe 17 a.

The ejector 40 has the suction function and pressurization function of the refrigerant flowing to the refrigerant jet hole 40 h, as is the case with the first embodiment. In addition, the first evaporator 19 evaporates this refrigerant to have a cooling capacity, which is then drawn into the compressor 11 again. The second evaporator 22 evaporates the refrigerant flowing from the branch portion K to the second evaporator 22, as is the case with the first embodiment, while the refrigerant is being drawn into the refrigerant suction port 40 b of the ejector 40.

As mentioned above, in the embodiment, likewise the first embodiment, the first evaporator 19 and the second evaporator 22 can perform the cooling operations simultaneously. Furthermore, the refrigerant evaporation pressure of the second evaporator 22 can be lower than that of the first evaporator 19.

Moreover, the refrigerant flowing from the refrigerant pipe 14 b to the ejector 40 is likely to flow into the refrigerant jet hole 40 h of the ejector 40. This embodiment can obtain the same effect as that of the first embodiment.

Since in the embodiment, the branch portion K is integrally formed with the inside of the ejector 40, it is not necessary to provide a branch portion for guiding the liquid-phase refrigerant to the nozzle 40 b side (the refrigerant jet hole 40 h) of the ejector 40, in the pipe of the refrigerant cycle device 10. Thus, even when the whole cycle is required to be installed in a narrow space, a pipe layout of the cycle can be simplified, thereby achieving reduction in size of the whole cycle.

Seventh Embodiment

In the seventh embodiment, as shown in FIG. 11, a vapor-liquid separator 33 is provided, and a branch-portion integrated ejector 40 as that of the sixth embodiment is also provided. Furthermore, the liquid-phase refrigerant outlet of the vapor-liquid separator 33 is connected to the refrigerant flow inlet 40 d, the branch refrigerant flow outlet 40 e is connected to the refrigerant pipe 17 a, and the refrigerant suction port 40 f is connected to the branch pipe 17 c.

Also, the direction of arrangement of the ejector 40 is the same as that of the sixth embodiment. The seventh embodiment may be the same as the fifth embodiment in other components except for the above-mentioned components, as shown in FIG. 11.

The refrigerant cycle with the above-mentioned arrangement of the embodiment is operated to cause the refrigerant discharged from the compressor 11 to be cooled by the condenser 12, and to be separated into the vapor-phase and liquid-phase refrigerants by the vapor-liquid separator 33. The liquid-phase refrigerant stored in the vapor-liquid separator 33 flows into the ejector 40, and is branched to the refrigerant jet hole 40 h and to the branch pipe 17 a at the branch portion K. As a result, the liquid-phase refrigerant can be supplied reliably to the refrigerant jet hole 40 h of the ejector 40. This embodiment can obtain the same advantages as that of the fifth embodiment.

Moreover, in the seventh embodiment, the pipe layout of the refrigerant cycle can be simplified, thereby achieving reduction in size of the whole cycle, as is the case with the sixth embodiment.

Other Embodiments

Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various modifications and variations can be made to the disclosed cycle as follows.

(1) Although in the first, second, and sixth embodiments, the space to be cooled of the first evaporator 19 is the same as that of the second evaporator 22, the space to be cooled of the first evaporator 19 may be different from that of the second evaporator 22. For example, the first evaporator 19 may be used for air conditioning in an interior of a vehicle, and the second evaporator 22 may be used for a refrigerator in the interior of the vehicle.

Furthermore, likewise the third to fifth and seventh embodiments, the first evaporator 19 may not be provided, and only the second evaporator 22 may be provided to have the cooling capacity.

(2) Although in the first and second embodiments, heat is exchanged in the inner heat exchanger 13 between the refrigerant passing through the refrigerant pipe 14 and the refrigerant on the suction side of the compressor 11, heat may be exchanged between the refrigerant passing through the refrigerant pipe 16 or the branch pipe 17 a, and the drawn refrigerant of the compressor 11.

Also in the third to fifth, and seventh embodiments, the inner heat exchanger 13 may be disposed so as to exchange heat between the refrigerant on the downstream side of the condenser 12, 31, 32, and the refrigerant on the suction side of the compressor 11.

(3) In the above-mentioned embodiments, the throttle means disposed in the branch pipe 17 is the fixed throttle 21, but a variable throttle mechanism capable of changing the refrigerant path area electrically and mechanically may be used. For example, in the structure of the first embodiment, the degree of supercooling of the refrigerant at the outlet side of the second evaporator 22 may be detected, and the degree of opening of the refrigerant path area may be controlled such that the supercooling degree detected is in a predetermined range.

(4) Although in the first to fifth embodiments, the fixed flow rate type ejector 18 is employed in which the refrigerant path area of the nozzle 18 a is not changed, the variable flow rate type ejector which can change the refrigerant path area of the nozzle 18 a electrically and mechanically may be used likewise the sixth and seventh embodiments. For example, in the structure of the first embodiment, the degree of supercooling of the refrigerant at the outlet of the condenser 12 may be detected, and the degree of opening of the refrigerant path area of the nozzle may be controlled such that the supercooling degree detected is in the predetermined range.

(5) The three-way joint 30 of the second embodiment is disposed such that the direction of the refrigerant flow from the refrigerant pipe 14 to the branch portion E (the direction of arrow F in FIG. 4) and the direction of the refrigerant flow from the branch portion E to the refrigerant pipe 16 (the direction of arrow G in FIG. 4) are oriented downward in the vertical direction on the same straight line in order to allow the liquid-phase refrigerant to flow readily from the branch portion E to the refrigerant pipe 16. However, the arrangement direction of the three-way joint 30 is not limited thereto.

For example, even when the refrigerant flow from the refrigerant pipe 14 to the branch portion E (the direction of arrow F in FIG. 4) and the refrigerant flow from the branch portion E to the refrigerant pipe 16 (the direction of arrow G in FIG. 4) are oriented horizontally on the same straight line, and when the refrigerant flow from the branch portion E to the branch pipe 17 a is oriented upward in the vertical direction, the same effect can be obtained.

In a case where the refrigerant speed is slow and is influenced strongly by the gravity even when only the direction of the refrigerant flow from the branch portion E to the refrigerant pipe 16 is oriented downward in the vertical direction, the same effect as that of the second embodiment can be obtained.

(6) Although in the sixth embodiment, the arrangement direction of the ejector 40 is set such that the direction of the refrigerant flow into the refrigerant jet hole 40 h is oriented downward in the vertical direction (in the direction of arrow N in FIG. 10), the arrangement direction may be changed.

For example, the direction of the refrigerant flow from the refrigerant pipe 14 b to the branch portion K (the direction of arrow L in FIG. 10), and the direction of the refrigerant flow from the branch portion K to the branch pipe 17 a (the direction of arrow M in FIG. 10) may be oriented upward in the vertical direction, and the direction of the refrigerant flow into the refrigerant jet hole 40 h (the direction of arrow N in FIG. 10) may be oriented horizontally. This makes it difficult for the refrigerant to flow in the direction from the branch portion K to the branch pipe 17 a due to the gravity, and makes it easy for the refrigerant to flow to the refrigerant jet hole 40 h. The same effect as that of the sixth embodiment can be obtained.

(7) With the above-mentioned structure of the ejector 40 of the sixth and seventh embodiments, the direction of the refrigerant flow from the branch portion K to the branch pipe 17 a and the direction of the refrigerant flow into the refrigerant jet hole 40 h may be substantially symmetrical with respect to the refrigerant flow from the refrigerant pipe 14 b to the branch portion K.

For example, when the direction of the refrigerant flow from the branch portion K to the branch pipe 17 a is oriented perpendicular to the direction of the refrigerant flow from the refrigerant pipe 14 b to the branch portion K, and to the direction of the refrigerant flow into the refrigerant jet hole 40 h (oriented in the front-back direction with respect to a paper surface of FIG. 10), any influences by the kinetic momentum in the refrigerant flow direction from the refrigerant pipe 14 b to the branch portion K can be eliminated, so that the same effect as that of the first embodiment can be obtained.

(8) Although in the above-mentioned sixth and seventh embodiments, the ejector 40 including the branch portion therein is employed, this ejector may be integrally formed with the fixed throttle 21 or the variable throttle mechanism disposed in the branch pipe 17. This can further simplify the pipe layout of the cycle, thereby achieving reduction in size of the whole cycle.

(9) Although in the above-mentioned embodiments, the variable displacement compressor is used as the compressor 11, a fixed displacement compressor or an electric compressor may be used. Furthermore, the fixed displacement compressor controls the refrigerant discharge capability by controlling a ratio (operating ratio) of an operational condition to a non-operational condition of the electromagnetic clutch. The electric compressor may control the refrigerant discharge capability by control of the number of revolutions.

(10) In the above-mentioned embodiments, the first evaporator 19 and the second evaporator 22 serve as indoor heat exchangers for cooling the space to be cooled, and the condensers 12, 31, and 32 serve as outdoor heat exchangers for radiating heat to the atmosphere. Conversely, the invention may be applied to an example (heat pump cycle) in which the first evaporator 19 and the second evaporator 22 may serve as outdoor heat exchangers for absorbing heat from a heat source, such as the atmosphere, and the condensers 12, 31, and 32 serve as indoor heat exchangers for heating a fluid to be heated, such as air or water.

In the refrigerant branch structure with the branch portion can be used for any refrigerant cycle devices with an ejector, with a cycle structure different from the above-described embodiments.

Furthermore, the term “substantially equal” described in the embodiments means not only that the ratio of the liquid-phase refrigerant in the refrigerant flowing to the ejector (18) side is completely identical to that of the liquid-phase refrigerant in the refrigerant flowing to the evaporator (22) side, but also that these rates may be substantially equal to each other even with a small difference.

Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims. 

1. A branch structure for a refrigerant cycle device having an ejector, the branch structure being provided on an upstream side of the ejector, for branching and supplying refrigerant to a nozzle of the ejector and to an evaporator connected to a refrigerant suction port of the ejector, the branch structure comprising: an introduction pipe part for introducing the refrigerant; and at least two arm parts branched out from the introduction pipe part, wherein the two arm parts are substantially symmetrical with respect to the introduction pipe part, while being positioned substantially under the same condition with respect to a direction of gravity.
 2. The branch structure according to claim 1, wherein the two arm parts are arranged substantially in a U shape having one end connected to the introduction pipe part.
 3. A branch structure for a refrigerant cycle device having an ejector, the branch structure being provided on an upstream side of the ejector for branching and supplying refrigerant to a nozzle of the ejector and to an evaporator connected to a refrigerant suction port of the ejector, the branch structure comprising: an introduction pipe part for introducing the refrigerant; and at least first and second branch parts branched out from the introduction pipe part, wherein the first branch part extends in an extension direction of the introduction pipe part, and the second branch part extends substantially perpendicularly to the extension direction of the introduction pipe part.
 4. The branch structure according to claim 3, wherein the introduction pipe is positioned so as to extend in the direction of gravity.
 5. The branch structure according to claim 3, wherein the second branch part is positioned to extend in a horizontal direction from an extension of the introduction part.
 6. A refrigerant cycle device comprising: a condenser for cooling and condensing refrigerant; a branch portion for branching a flow of refrigerant on a downstream side of the condenser into first and second streams; an ejector that includes a nozzle for decompressing and expanding refrigerant of the first stream flowing from the branch portion, and a refrigerant suction port from which refrigerant is drawn by a high-speed refrigerant flow jetted from the nozzle; a throttle member for decompressing and expanding refrigerant of the second stream flowing from the branch portion; and an evaporator for evaporating refrigerant decompressed by the throttle member, the evaporator having an outlet coupled to the refrigerant suction port, wherein the branch portion branches the refrigerant flow such that a ratio of a liquid-phase refrigerant in refrigerant flowing to the nozzle is approximately equal to a ratio of a liquid-phase refrigerant in refrigerant flowing to the evaporator.
 7. The refrigerant cycle device according to claim 6, wherein a flow direction of the refrigerant flowing from the branch portion toward the nozzle, and a flow direction of the refrigerant flowing from the branch portion toward the evaporator are arranged substantially on the same plane.
 8. The refrigerant cycle device according to claim 6, wherein the flow direction of the refrigerant flowing from the branch portion toward the nozzle, and the flow direction of the refrigerant flowing from the branch portion toward the evaporator are arranged substantially symmetrically with respect to a flow direction of the refrigerant flowing into the branch portion.
 9. The refrigerant cycle device according to claim 6, wherein: the branch portion is constructed with an introduction pipe part for introducing refrigerant, and at least two arm parts branched out from the introduction pipe part; and the two arm parts are substantially symmetrical with respect to the introduction pipe part, while being positioned substantially under the same condition with respect to a direction of gravity.
 10. A refrigerant cycle device comprising: a condenser for cooling and condensing refrigerant; a branch portion for branching a flow of refrigerant on a downstream side of the condenser; an ejector that includes a nozzle for decompressing and expanding refrigerant of the first stream flowing from the branch portion, and a refrigerant suction port from which refrigerant is drawn by a high-speed refrigerant flow ejected from the nozzle; a throttle member for decompressing and expanding refrigerant of the second stream from the branch portion; and an evaporator for evaporating refrigerant decompressed by the throttle member, the evaporator having an outlet coupled to the refrigerant suction port, wherein the branch portion branches the refrigerant flow such that a ratio of a liquid-phase refrigerant in refrigerant flowing to the nozzle is equal to or greater than a ratio of a liquid-phase refrigerant in the refrigerant flowing to the evaporator.
 11. The refrigerant cycle device according to claim 10, wherein a flow direction of refrigerant flowing into the branch portion is arranged on a substantially same straight line as a flow direction of refrigerant flowing to the nozzle from the branch portion.
 12. The refrigerant cycle device according to claim 10, wherein the flow direction of refrigerant flowing to the nozzle from the branch portion is oriented downward substantially in a vertical direction.
 13. The refrigerant cycle device according to claim 10, wherein: the branch portion is constructed with an introduction pipe part for introducing the refrigerant, and at least first and second branch parts branched out from the introduction pipe part; and the first branch part extends in an extension direction of the introduction pipe part, and the second branch part extends substantially perpendicularly to the extension direction of the introduction pipe part.
 14. A refrigerant cycle device comprising: a compressor for compressing and discharging refrigerant; a branch portion for branching a flow of refrigerant discharged from the compressor in a vapor-phase condition or a vapor-liquid two-phase condition near a saturated vapor line, into first and second streams; a first condensing part for cooling and condensing refrigerant of the first stream branched by the branch portion; a second condensing part for cooling and condensing refrigerant of the second stream branched by the branch portion; an ejector that includes a nozzle for decompressing and expanding refrigerant flowing from the first condensing part, and a refrigerant suction port from which refrigerant is drawn by high-speed refrigerant flow ejected from the nozzle; a throttle member for decompressing and expanding the refrigerant flowing from the second condensing part; and an evaporator for evaporating refrigerant decompressed by the throttle member, wherein the evaporator has an outlet coupled to the refrigerant suction port.
 15. The refrigerant cycle device according to claim 14, wherein the branch portion is provided between a discharge port of the compressor and an upstream side of the first and second condensing parts in a refrigerant flow.
 16. The refrigerant cycle device according to claim 14, wherein: the first and second condensing parts are constructed to form a condenser; and the branch portion is provided on a refrigerant inlet side inside the condenser.
 17. A refrigerant cycle device comprising: a condenser for cooling and condensing refrigerant; a vapor-liquid separator for separating the refrigerant on a downstream side of the condenser into a vapor-phase refrigerant and a liquid-phase refrigerant, and for allowing the liquid-phase refrigerant to flow out therefrom; a branch portion for branching a flow of the liquid-phase refrigerant from the vapor-liquid separator into first and second streams; an ejector that includes a nozzle for decompressing and expanding liquid refrigerant flowing from the first stream, and a refrigerant suction port from which refrigerant is drawn by high-speed refrigerant flow ejected from the nozzle; a throttle member for decompressing and expanding liquid refrigerant flowing from the second stream; and an evaporator for evaporating refrigerant decompressed by the throttle member, wherein the evaporator has a refrigerant outlet coupled to the refrigerant suction port.
 18. The refrigerant cycle device according to claim 17, wherein: the vapor-liquid separator includes a receiver for receiving liquid-phase refrigerant; and the branch portion is provided in the receiver.
 19. The refrigerant cycle device according to claim 17, wherein the branch portion is located on a downstream side of a liquid-phase refrigerant outlet of the vapor-liquid separator.
 20. The refrigerant cycle device according to claim 10, wherein the branch portion is provided integrally with the ejector. 